Warheads may be directed against a wide spectrum of targets. There are soft targets which can include personnel or aircraft, and there are hard targets which may include anti-aircraft gun emplacements, missile warheads, tanks, etc. Between these two extremes, there are a multitude of targets.
One of the factors determining whether a particular warhead will be effective against a particular target is the size of the fragments produced upon detonation of the explosive within the warhead. In general, the softer the target, the smaller the fragments can be.
Warhead fragment size can be predetermined. This has been done, for example, by pre-grooving the interior surface of the warhead casing. When the casing alone is grooved, the casing groove pattern determines the fragment size.
One example of a reference that discloses a warhead which can generate different sizes of explosive fragments is U.S. Pat. No. 4,312,274. Another example of such a reference is U.S. Pat. No. 7,743,707.